I did my undergraduate studies at Harvard and my medical training at the University of Pennsylvania. My internship was in Cooperstown, New York, then considered an “experiment in rural medicine”. During my obligatory national service, I was assigned to the National Institutes of Health (NIH) as a U.S. Public Health Service Officer, where I remained for 12 years. I began in molecular spectroscopy, but when NIH sent me to El Salvador for two years to help modernize a medical school, I found a serious area of interest in tropical medicine, which continued for thirty years. On emigrating to Israel, most of my work was in leishmaniasis. My background in Cooperstown and El Salvador was my calling to be Director of Israel’s only School of Public Health and be Chair of the planning committee for the new community-oriented School of Medicine in Beersheva. However, when one day I was asked if it was possible to retrieve DNA from a mummy, I opened a new field, the “ancient DNA” of pathogens. The organisms which tempted us most were the Mycobacteria, M. tuberculosis and M. lepra. From TB, the disease, it was a short hop to BCG for its prevention. As I learned more, it was apparent that this very old vaccination had non-specific effects. In the case of this proposal, it is the prevention of Alzheimer’s Disease.